Hydraulic apparatus



Jan.22, 1929. 9 1 1,699,917

T. C, POMEROY HYDRAULI C APPARATUS Filled Nov. 8', 1924 [N VEN ToR 7/MOTHY G. PoMERo Y Patented Jan. 22, 1.929.

UNITED STATES TIMOTHY CYRIL POIEBOY, QF IOLINE, ILLINOIS, ABSIGNOR OF ONE-THIRD '1.0`

JEBEHIAH E. IADDEN, l' CHICAGO, ILLINOIS.

HYDRAULIC APPARATUS.

Application filed November 8, 1924. Serial lo. 748,877.

This invention relates to new and useful im rovements in hydraulic apparatus such as.

hy raulic jacks, pumps, rams, etc. employing a liquid medium to transmit power` and more yparticularly relates to hydraulic liftingjacks such as are commonly employed for liftmg the wheels and axles of automobiles, trucks,

etc. e

An object of the invention is to provide means operable in conjunction with such devices whereby the operatin liquid contained therein, will automaticall e returned to its source when the movabe member therein reaches the limit of its effective stroke, thereby preventing the apparatus from being subjected to unnecessary strains as a result of excessive internal pressure caused by oo ntinued pumping or forcing of the liquid against the movable member after having 20 reached said limit.

A further and more specific object of the invention is to provide a hydraulic device having a plunger operatively mounted therein which is provided with a valve mechanism adapted to be actuated when the plunger reaches the limit of its effective or work stroke, thereby allowing a pxortion of the liquid to escape from beneath t e plunger and thus eliminate any danger of an excessive pressure being built up within the device, which might result in serious damage thereto.

A further object of the invention is to provide a liquid release valve-mechanism of simple and inexpensive construction which is particularly adaptable for use in conjunction with such hydraulic devices as the lifting 'ack shown and described -in the prior pen in joint application of the inventor hereof an Carl E. Johnson, filed August 28, 1924, Serial No. 734,730.

The particular object of the invention therefore is to provide a simple and improved mea-ns' operable in conjunction with a hydraulic device to render such device eilicient and foolroof in operation. v

Ot er objects of the invention will appear fromv the following description and the accompanying drawings and will be pointed out in the annexed claims. 50 In the drawings, there has been disclosed a structure designed to carry out the various objects of the invention but' it is to be understood that the invention is not confined to the exact features shown, as various changes may befmade within the scope of the claims which follow.

In the drawings:

Fi ure 1 is a viewin sectional elevation of a hy raulic jack showing my` invention applied thereto;

Figure 2 is a sectional view on the line 272 of Figure 1 showing the means for actating the valve mechanism;

Figure 3 is a cross-sectional view on the line 3-3 0f Figure 2; and c Figure 4 shows a valve-mechanism of modified construction. l

In the selected embodiment of the invention here shown there is illustrated, for purposes-of disclosure, a form of jack such as the one shown `in the above mentioned prior pending application, Serial No. 734,730. This jack comprises a cylinder 4 mounted in a suitable base 5 and havin a piston rod 6 slidably mounted therein. T e lower end of the piston rod 6 has a plate 7 secured thereto and a leather cup or acking 8 is mounted on the lower face of this plate as shown in Figure 1.

A lifting head 9 is mounted on the upper end of the piston rod and a discharge tube 11 and an intake tube 12 are mounted within/the piston rod and have their upper ends secured to the lifting head 9 by such means as the threads 13. The lower ends of the tubes 11 and 12 pass through apertures provided in the plate 7 and packing 8, and also throu h a relaivtelysmaller plate or washer 14. The lower ends of the tubes are threaded to receive the nuts 15 and 16 by means of which the lifting head, piston rod, plate 7 packin 8 and washer 9 may be securely tied tog'et er for operation as a unit. It will be noted that the nut 15 is open at the bottom so that the lower portion of the cylinder 4 will be in communication with the lifting head 9 through the discharge tube 11, and that the 'nut 16 -on the lower end of the intake tube provides a closure for the end of said tube.

v A (passage 17 is provided in the lifting head 9 an 19 connects the upper end of the discharge tube 11 with the horizontal duct 18. Suitable check valves 21 and 22 are provided in the horizontal duct 18 and the passage 17, res ectively, as shown in the upper portion of igure 1. These valves function to prevent the operating fluid contained within the jack, from returning to the interior of the piston rod when the jack is being operatedl to lift a load.

The means provided for pumping the fluid from the interior of the piston rod to beneath the iston head resides in the provision of a disp acement pump mounted Within a section of the jack handle which preferably is made in two sections as shown. The intermediate handle section 23 is pivotally secured to the lifting head by means of a tapered plug valve 24, the construction of which is clearly shown in the above-mentioned prior pending application and it is therefore not necessary that thisv pivotal joint be here shown in detail. The outer or pump section 25 of the handle is similarly connected to the intermediate handle section 23 by means of a tapered valve plug 26 similar in construction to the pivot 24 connecting the intermediate handle section to the lifting head of the jack. A pump rod 27 is reciprocally mounted within the handle section 25 and has an operating handle 28 secured to the uper end thereby whereby it may be manually actuated when it is deslred to raise the lifting head of the ack. A suitable packing box 29 is provided in the handle section 25 to prevent the leakage of oil from the handle when the pump rod is being actuated.

In the operation of the form of jack here showniluid is drawn from the interior of the piston rod through a port 31 provided in the'wall of theV intake tube 12 adjacent the lower end thereof, thence upwardly through the tube through the vertical passage 17, by the check valve 22, through the horizontal duct 18, and into the tapered plug 24 connecting the handle to the lifting head.` VFrom the tapered plug it is drawn through an aperture 32 provided in the plugand into the relatively larger intermediate handle section 23, thence through the joint 26 and into the pump section 25 of the handle, substantially following the pump rod 27 as it is upwardly drawn in the pump section 25 of the handle. The pum rod 27'is then downwardly forced against tie fluid with the result that such fluid will be forced out` of the yhandle and back through the tapered plug24, through the horizontal duct 18, by the check valve 21, and into the assage 19, thence downwardly through t e discharge tube 11 and into the bottom ofl the cylinder beneath the piston head.y Such pumping of the liquid from within the piston rod to a point beneath the piston head will cause the latter to gradually ascend. Itis to be understood that during the operation of the pum the check valves 21 and 22 will yalternate y close and open as the fluid is drawn from the piston rod a-nd pumped into the lower portion of the cylinder. Suitable-means are provided in jacks of this type to permit the return of the oil from the cylinder back to tliepiston but l as this part of the jack forms no part of the present invention, I have thought it unnecessary to show same in detail, it being understood that such means are provided.

An important feature of this invention resides in the novel means provided for preventing excessive pressure from belng built .l

-is mounted in the piston head and has itsI upper end in threaded engagement with the plate 7. A suitable packing washer 34 is preferably interposed between the fianged head 35 of the sleeve and the Washer 14 in order that a tight joint may be provided therebetween to prevent the leakage of oil therethrough. A conical valve seat 36 is formedin the lower endof the sleeve 33 and has a ball check valve 37 yieldably seated therein by means of a tension, spring 38 having its other end secured to a stud 39 by a screw 41 (Figure 3). The stud 39 is similarly secured to the plate 7 by having its upper'end in threaded engagement therewith, as shown. A packing 34 is likewise provided under the head of the stud 39 to revent leakage through the piston head. lhe spring 38 functionsv normally to retain the ball 37 in closed inoperative position.

The means provided for actuating the valve 37 when the piston rod reaches the limit of its upward movement consists of a rod 42 which is transversely mounted within the piston rod and has its ends outwardly projecting through the .wall thereof through elongated openings 43. A relatively smaller rod 44 is interposed between the transverse rod 42 and the ball check valve 3 7 so that when the rod 42 is downwardly moved within the piston rod the valve will be downwardly moved to open position against the tension of the spring 38. l

Referring to the drawings, it will be noted that the upper major portion of the piston rod is of a-relatively smaller diameter than upper end of the cylinder in abutting rela-` tion thereto. A packing 47 is mounted above the detent 46 and is compressed against the walls of the piston rod by means ofa packing f that it will prevent the nut 48 which is in threadedengagement with the up er end of the cylinder 4.

In t e operation of a jack or other hydraulically-operated 'device employing this novel fluid releasing valve mechanism, the

piston or movable member therein will be raised by umping or forcing the fluid under the mova le member as hereinbefore described. As soon asthe piston or movable member reaches the uppermost limit of its lifting or work stroke, the ends of the transverse rod 42 will engage the detent ring 46 thereby downwardly forcing the rod 44 against the ball check valve 37 with the result that the valve will be opened to allow a portion of the fluid being pumped under the pis)- ton head to escape through the valve and back to the interior of the piston rod. Thus it will readily be seen that by the employment of this novel fluid releasing mechanism, it will be impossible for an inexperienced operator or novice to injure or damage the jack or other hydraulic device with which 1t is used by the continued pumping or forcing of fluid under the movable member, as a result of the fluid being permitted to escape through the valve sleeve 33 and back to the interior of the piston rod or its source. As soon as the operator ceases 4to actuate the pump rod 27, the spring 28 will immediately cause the valve 37 to be closed so that the piston rod will remain in load-lifting position and will thus remain until the mechanism provided for returning the fluid from beneath the piston has been actuated by manipulation of the handle or other means, not shown.

This novel device is of further value in umping means from becoming ino erative by losing its prime which might e caused by the leakage of fluid from the apparatus when compressed to an excessively high pressure. Therefore, by thus preventing excessive pressures from being built up within the apparatus, such apparatus will be rendered substantially fool-proof. v

In Figure 4, there is shown a modified construction employing a hollow stud 49 having a conical valve seat 51 provided at its upper end against which a ball valve 52 is seated by means of a compression spring 53 interposed between the ball 52 and a cap 54 secured to the lower end of the stud 49. A

- valve-actuating rod 55 has one end in en- 45 of the piston rod so that when the piston rod is upwardly -mved within the cylinder the end gof the valve actuating rod will engage the annular detent ring 46 at the upper end of the cylinder and t ereby cause the valve 52 to be opened. Such opening of the valve 52 will permit the fluid pumped beneath the iston head to escape throu h an aperture 5 provided in the cap 542m upwardly through the hollow stud 49 and by the open valve 52 and thence into the hollow piston rod thereby causing the pressure beneath the piston head to lie lessened.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is: y

1. In a hydraulic device, the combination of a stationaryl cylinder, a hollow plun er mounted to reciprocate within the cylin er and )rovided at one end with a piston head, a fluid transferable to the cylinder from the interior of the lun er, a valve-controlled conduit within t e p unger for withdrawal dof fluid therefrom and having its intake positioned adjacent to the piston head, a valvecontrolled conduit for delivering fluid tothe cylinder beneath the piston head, a pump operatively connected with both of said conduits for discharge of fluid from the plunger through one conduit and delivering it to the cylinder beneath the piston head through the other conduit, a normally closed valve 1n the piston head, and operating means for said valve positioned above the intake of said first mentioned conduit and adapted to be engaged by stationary means to open said valve v to prevent the withdrawal of all the fluid from the plunger and loss of prime in the pump.

2. In a hydraulic device, the combination of a stationary cylinder, a hollow plun er mounted to reciprocate within the cylin er and provided at one end with a liftin member and at its other end with a pistonliead, a fluid transferable to the cylinder from .the interior of the plunger, a valve-controlled conduit for discharge of fluid from the plunger and having its intake positioned ad- `jacent to the piston head. a valve-controlled conduit for delivering fluid to the cylinder beneath the piston head, al pump operatively connected with both of said conduits for discharge of fluid from the plunger through one conduit and delivering it to the cylinder beneath the piston head through the other conduit, a normally closed spring-actuated valve in the piston head of the hollow plunger, and avalve-actuating member operatively con- 'tnected' with said valve and positloned above the intake to said first mentioned conduit and protruding through the wall of said hollow plunger and adapted to be lengaged by stai tionary means to open said valve to prevent withdrawal of all the fluid from the plunger to prevent loss of prime in the pum 3. In a hydraulic device, the com ination of a stationary cylinder, a hollow piston mem ber mounted to reciprocate within the cylinder and provided with a lifting head, a fluid transferable to the cylinder from the interior vsaid conduits being positioned within they hollow piston and communicable one with the other t nough :the piston lifting head, the. discharge conduit having an intake ort posi- '.tioned adjacent to' the piston hea for passage of iuid from the hollow piston into said conduit, a pump operatlvely connected with y`both of' said conduits for withdrawal o-fluid from the hollow piston throu h one conduit and delivering it to the cylin cr beneath the piston head'through the other conduit, and a normally closed valve in the vpiston head operable at a predetermined point inthe travel of the iston to o en communication for flow of fluid between e cylinder and the hollow piston through the iston head and maintain suicient'luid in t e hollow piston between the intake of the dischar e conduit and adjacent face of the piston hea to insure a prime for the pump throughout the lifting stroke of the piston.

In witness whereof, I have hereunto setmy hand this 3rd day of November, 1924.

TIMOTHY CYRIL -POMERQY. 

